Hey guys sounds like this threads a bit old but i am using an e-pc with the in-car laptop power supply. Ive had no problems at all. I just wired to acc. power so i just kill the power without shutting down and when i turn the ignition back on it boots itself up again. I know its dodgy but XP has had no problems so far and ive been running it for about 6 months.

By the way does anyone have a spare case or even just the internal chassis for these pc's? I "modified" mine to bolt into my glovebox and now want to put it back in the case as im upgrading to a P4...

Try putting a 2.5" Drive in there (Runs off 5v) and powering it straight off 12v
Thats what I do and it works briliantly, survives crank and all!
Cant use any 12v devices tho as the 12v rail drops to 10ish volts...
No laptop power brick or inverter needed!

time to resurect this thread. Do most of you shutdown your e-pc when your car is off? My battery has died like four times. I think it might be time to invest in a second battery which leads to another question. If i do, I plan to have a relay connect the second batt and carputer when the ignition is on. How do i determine how many amps the relay I am going to use should be?

I use a relay rated at 15 amps to isolate my 2nd battery from the 12volt accessory supply. I'd suggest a bosch type relay available from most autopart stores for <$10 they are rated for 30A.
looka this http://www.the12volt.com/relays/relays.asp

Operating notes.
From the drivers seat I can press the power switch for the inverter.
Choose to run off the cars electrical system or just off of the second battery by turning on the headlights. I like this solution because it provides an audible warning if I leave the headlights on and try to leave the car.
The 7 AH battery will give me 30-45 minutes of run time.

This config is about a year and a half old and has given me no trouble.
I was careful to measure the power drawn by the pc and choose components accordingly.

I might upgrade to a larger battery in the future and will definately add a 110vac to 15vdc psu to charge/power the system when I'm parked overnight in the garage.

Thanks for the info Billmee. I've got a few 30A bosch relays laying around somewhere. How did you determine the size of the relay you need? I have a bunch of those sealed gel cell batteries but if they only last 20-30min each, i think i'm going to go with another full sized car battery. The thing that sucks is that i have alot of those batteries and i have the perfect spot to hide them.

Talon - I'm guessing you are refering to power adapters. I tried a kensington laptop adaptor that was able to deliver 4 amps @ 18v (was able to change the voltage with different "chips". The problems with that one was it shut off when i start my car and it drew ALOT from my battery.

I also tried a 65w targus adaptor. It was less than a half inch thick, supplied multiple voltages at once and the output was rock solid even when the input voltage was eight volts. The only problem was it shut off when i tried connecting the epc to it. It wasnt able to supply enough power.

Right now I have the epc powered directly off of the car. It survives engine starting about 50% of the time. Out of curiosity, would a capacitor close to the computer help this at all?

Thanks for the info Billmee. I've got a few 30A bosch relays laying around somewhere. How did you determine the size of the relay you need? I have a bunch of those sealed gel cell batteries but if they only last 20-30min each, i think i'm going to go with another full sized car battery. The thing that sucks is that i have alot of those batteries and i have the perfect spot to hide them.

If you decide to use a full size battery you are going to have to chuck most of my suggestions.

You will gain a lot of run time but you are taking it to the next level.

Plan on running a dedicated low gauge wire from the first battery, either a tank circuit or a true isolator. Search for tank circuit and second battery to get more details. Good luck and have fun

At the moment I dont see me being able to run the EPC 24/7. When i boot the machine it gives me errors about the mouse/keyboard not being plugged in. I took the circuit board out of a keyboard and the keyboard error went away. if i simply attach a usb to ps/2 adapter, would that solve anything? I tried an adapter that allows you to connect ps/2 keyboard and mouse into a usb port and the computer still gave me an error.